The present embodiments generally pertain to an apparatus, methods, and/or systems for improving heat exchange. More particularly, but not by way of limitation, the present embodiments relate to spiral wound cross-flow heat exchangers, which may be used for example in a gas turbine engine, for fluid-fluid heat exchange. As one skilled in the art will understand, while various embodiments are described relative to a gas turbine engine, the apparatus, methods and/or systems may also be used in various alternative applications where it is desired that heat be exchanged between two fluids.
In a gas turbine engine, air is pressurized in a compressor and mixed with fuel in a combustor for generating hot combustion gases which flow downstream through turbine stages. A typical gas turbine engine generally possesses a forward end and an aft end with its several core or propulsion components positioned axially therebetween. An air inlet or intake is located at a forward end of the gas turbine engine. Moving toward the aft end, in order, the intake is followed by a compressor, a combustion chamber, and a turbine. It will be readily apparent from those skilled in the art that additional components may also be included in the engine, such as, for example, low pressure and high pressure compressors, and low pressure and high pressure turbines. This, however, is not an exhaustive list.
It is necessary to manage heat generation within a gas turbine engine so as not to raise engine temperatures to unacceptable levels. For example, it may be desirable to control oil temperatures within the gas turbine engine which lubricates bearings associated with the high pressure shaft and/or the low pressure shaft. Further, during operation, significant heat is generated by the high pressure compressor which generates high temperature flow. Therefore, it may also be desirable to cool air exiting one or both of the high pressure compressor and the low pressure compressor.
In order to cool these fluids, various methods have been used however, improvements are still desirable. For example, improvement of parameters which are continually sought for heat exchangers include, but are not limited to, decreased weight, decreased volume, decreased pressure drop across the heat exchangers and decreased resistivity to thermal exchange. Another parameter which is pertinent is to heat exchangers heat rejection during operation.
It would be desirable to provide a heat exchanger for two or more fluid flows which prevent fluid mixing but which satisfies parameters to improve heat exchange between the two or more fluids and is formed of a shell-tube construction.
The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of the instant embodiments are to be bound.